Defect-level trap optimization in Cu2ZnSn(S,Se)4 photovoltaic materials via Sb3+-doping for over 13% efficiency solar cells

Abstract

In this study, Sb₂S₃ was introduced into the two-step selenization process to promote bottom grain growth and reduce the surface roughness of the Cu₂ZnSn(S,Se)₄ light-absorber layer. The introduction of Sb doping in Cu₂ZnSn(S,Se)₄ can passivate bulk and interface defects and a small conduction band offset (CBO) can be found, which facilitate the improvement of heterojunction carrier transport properties. Similarly, simulations illustrated that Sb doping improved device efficiency by controlling bulk and interface defects and band alignment. This optimized method facilitated the penetration of Sb, resulting in a high-quality CZTSSe absorber layer. Ultimately, the research culminated in a significant enhancement, yielding a solar cell with an impressive efficiency of 13.11%. These findings offer new possibilities for kesterite solar cells and advance the potential of CZTSSe materials in thin film photovoltaic applications.